Thermoplastic molding compositions containing polycarbonates and ABS (acrylonitrile/butadiene/styrene) have been known for a long time. Thus, U.S. Pat. No. 3,130,177 A describes readily processable molding compositions of polycarbonates and graft polymers of monomer mixtures of acrylonitrile and an aromatic vinyl hydrocarbon on polybutadiene.
WO 91/18052 A1 discloses PC/ABS compositions having a high heat stability, which are characterized in that the graft polymers have a sodium ion and potassium ion content of less than 1,500 ppm, preferably less than 800 ppm, and comprise a certain amount of antioxidants. The lithium ion content of the composition or graft polymer is not disclosed.
WO 99/11713 A1 discloses flameproofed PC/ABS compositions having an improved resistance to moisture and at the same time a high level of mechanical properties, which are characterized in that the graft polymers have a content of alkali metals of less than 1 ppm. In particular, the sodium ion and potassium ion content of the graft polymer should be less than 1 ppm. The lithium ion content of the composition or graft polymer is not disclosed.
WO 00/39210 A1 discloses impact-modified flameproofed PC compositions comprising a reinforcing substance which have an improved resistance to moisture and at the same time a high level of mechanical properties, which are characterized in that the styrene resins have a content of alkali metals of less than 1 ppm. In particular, the sodium ion and potassium ion content of the styrene resin should be less than 1 ppm. The lithium ion content of the composition or styrene resin is not disclosed. An object of the invention is to provide PC/ABS molding compositions having an improved stability to hydrolysis for the production of complex moldings.
WO 2007/009622 A1 discloses impact-modified molding compositions with improved hydrolysis resistance containing polycarbonate and ABS, and having a low level of lithium impurities.